Liquid crystal display (LCD) becomes popular products on the market duet to its environment friendly properties of lighter and thinner design, lower power consumption and multi-functions.
In the technical field of LCD, since normal viewing region of the LCD is restricted solely to a narrow front view, those viewers at further left or right side of the display cannot see the displayed information on the LCD clearly or at all, which could provide certain protection for the privacy of the information shown in the LCD. But those who get confidential information from the computer intentionally or unintentionally often watch it directly behind the user or capture it with a hidden camera so as to steal the information displayed on the LCD. The peeper may have a clear view of the information displayed on the LCD from a certain angle without any awareness from the user.